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Wed, 21 Jan 2026 13:56:41 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id mixHLBnbcGkTSgAAD6G6ig (envelope-from ); Wed, 21 Jan 2026 13:56:41 +0000 Message-ID: Date: Wed, 21 Jan 2026 14:56:41 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 10/21] slab: remove cpu (partial) slabs usage from allocation paths Content-Language: en-US To: Suren Baghdasaryan Cc: Harry Yoo , Petr Tesarik , Christoph Lameter , David Rientjes , Roman Gushchin , Hao Li , Andrew Morton , Uladzislau Rezki , "Liam R. Howlett" , Sebastian Andrzej Siewior , Alexei Starovoitov , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev, bpf@vger.kernel.org, kasan-dev@googlegroups.com References: <20260116-sheaves-for-all-v3-0-5595cb000772@suse.cz> <20260116-sheaves-for-all-v3-10-5595cb000772@suse.cz> From: Vlastimil Babka Autocrypt: addr=vbabka@suse.cz; keydata= xsFNBFZdmxYBEADsw/SiUSjB0dM+vSh95UkgcHjzEVBlby/Fg+g42O7LAEkCYXi/vvq31JTB KxRWDHX0R2tgpFDXHnzZcQywawu8eSq0LxzxFNYMvtB7sV1pxYwej2qx9B75qW2plBs+7+YB 87tMFA+u+L4Z5xAzIimfLD5EKC56kJ1CsXlM8S/LHcmdD9Ctkn3trYDNnat0eoAcfPIP2OZ+ 9oe9IF/R28zmh0ifLXyJQQz5ofdj4bPf8ecEW0rhcqHfTD8k4yK0xxt3xW+6Exqp9n9bydiy tcSAw/TahjW6yrA+6JhSBv1v2tIm+itQc073zjSX8OFL51qQVzRFr7H2UQG33lw2QrvHRXqD Ot7ViKam7v0Ho9wEWiQOOZlHItOOXFphWb2yq3nzrKe45oWoSgkxKb97MVsQ+q2SYjJRBBH4 8qKhphADYxkIP6yut/eaj9ImvRUZZRi0DTc8xfnvHGTjKbJzC2xpFcY0DQbZzuwsIZ8OPJCc LM4S7mT25NE5kUTG/TKQCk922vRdGVMoLA7dIQrgXnRXtyT61sg8PG4wcfOnuWf8577aXP1x 6mzw3/jh3F+oSBHb/GcLC7mvWreJifUL2gEdssGfXhGWBo6zLS3qhgtwjay0Jl+kza1lo+Cv BB2T79D4WGdDuVa4eOrQ02TxqGN7G0Biz5ZLRSFzQSQwLn8fbwARAQABzSBWbGFzdGltaWwg QmFia2EgPHZiYWJrYUBzdXNlLmN6PsLBlAQTAQoAPgIbAwULCQgHAwUVCgkICwUWAgMBAAIe AQIXgBYhBKlA1DSZLC6OmRA9UCJPp+fMgqZkBQJnyBr8BQka0IFQAAoJECJPp+fMgqZkqmMQ AIbGN95ptUMUvo6aAdhxaOCHXp1DfIBuIOK/zpx8ylY4pOwu3GRe4dQ8u4XS9gaZ96Gj4bC+ jwWcSmn+TjtKW3rH1dRKopvC07tSJIGGVyw7ieV/5cbFffA8NL0ILowzVg8w1ipnz1VTkWDr 2zcfslxJsJ6vhXw5/npcY0ldeC1E8f6UUoa4eyoskd70vO0wOAoGd02ZkJoox3F5ODM0kjHu Y97VLOa3GG66lh+ZEelVZEujHfKceCw9G3PMvEzyLFbXvSOigZQMdKzQ8D/OChwqig8wFBmV QCPS4yDdmZP3oeDHRjJ9jvMUKoYODiNKsl2F+xXwyRM2qoKRqFlhCn4usVd1+wmv9iLV8nPs 2Db1ZIa49fJet3Sk3PN4bV1rAPuWvtbuTBN39Q/6MgkLTYHb84HyFKw14Rqe5YorrBLbF3rl M51Dpf6Egu1yTJDHCTEwePWug4XI11FT8lK0LNnHNpbhTCYRjX73iWOnFraJNcURld1jL1nV r/LRD+/e2gNtSTPK0Qkon6HcOBZnxRoqtazTU6YQRmGlT0v+rukj/cn5sToYibWLn+RoV1CE Qj6tApOiHBkpEsCzHGu+iDQ1WT0Idtdynst738f/uCeCMkdRu4WMZjteQaqvARFwCy3P/jpK uvzMtves5HvZw33ZwOtMCgbpce00DaET4y/UzsBNBFsZNTUBCACfQfpSsWJZyi+SHoRdVyX5 J6rI7okc4+b571a7RXD5UhS9dlVRVVAtrU9ANSLqPTQKGVxHrqD39XSw8hxK61pw8p90pg4G /N3iuWEvyt+t0SxDDkClnGsDyRhlUyEWYFEoBrrCizbmahOUwqkJbNMfzj5Y7n7OIJOxNRkB IBOjPdF26dMP69BwePQao1M8Acrrex9sAHYjQGyVmReRjVEtv9iG4DoTsnIR3amKVk6si4Ea X/mrapJqSCcBUVYUFH8M7bsm4CSxier5ofy8jTEa/CfvkqpKThTMCQPNZKY7hke5qEq1CBk2 wxhX48ZrJEFf1v3NuV3OimgsF2odzieNABEBAAHCwXwEGAEKACYCGwwWIQSpQNQ0mSwujpkQ PVAiT6fnzIKmZAUCZ8gcVAUJFhTonwAKCRAiT6fnzIKmZLY8D/9uo3Ut9yi2YCuASWxr7QQZ lJCViArjymbxYB5NdOeC50/0gnhK4pgdHlE2MdwF6o34x7TPFGpjNFvycZqccSQPJ/gibwNA zx3q9vJT4Vw+YbiyS53iSBLXMweeVV1Jd9IjAoL+EqB0cbxoFXvnjkvP1foiiF5r73jCd4PR rD+GoX5BZ7AZmFYmuJYBm28STM2NA6LhT0X+2su16f/HtummENKcMwom0hNu3MBNPUOrujtW khQrWcJNAAsy4yMoJ2Lw51T/5X5Hc7jQ9da9fyqu+phqlVtn70qpPvgWy4HRhr25fCAEXZDp xG4RNmTm+pqorHOqhBkI7wA7P/nyPo7ZEc3L+ZkQ37u0nlOyrjbNUniPGxPxv1imVq8IyycG AN5FaFxtiELK22gvudghLJaDiRBhn8/AhXc642/Z/yIpizE2xG4KU4AXzb6C+o7LX/WmmsWP Ly6jamSg6tvrdo4/e87lUedEqCtrp2o1xpn5zongf6cQkaLZKQcBQnPmgHO5OG8+50u88D9I rywqgzTUhHFKKF6/9L/lYtrNcHU8Z6Y4Ju/MLUiNYkmtrGIMnkjKCiRqlRrZE/v5YFHbayRD dJKXobXTtCBYpLJM4ZYRpGZXne/FAtWNe4KbNJJqxMvrTOrnIatPj8NhBVI0RSJRsbilh6TE m6M14QORSWTLRg== In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspamd-Action: no action X-Rspam-User: X-Rspamd-Queue-Id: 9DEAF40003 X-Rspamd-Server: rspam11 X-Stat-Signature: ncwh9gyqh4nsbneocxji1ie8gji5wmef X-HE-Tag: 1769003803-619998 X-HE-Meta: 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 ye9LndSl sIKXC8sJMltwe/pAc7PDWT1CtxP39H0GOxNy6fsnAAoFJhzD4YOJGkafGhj+BiafyyVxKvE6pQV8yHbGTFA+CsankFMfe7yTrP41V4SwoLM5Dq5/Nim6Xzf4Rw4AL3UrcMd0QHQ07+7xpG3z44fiwuzzGOioJ6Nbg11++qBp1TxriB36SvwToLiZFNSoSU+t8Lq4l3dWKVdPjuB0eVCiMpXDZ3UM5tUqLWUy7tQocLevxRmodudo4FFxlJ8wd/asKVCifFCRBCmfAmcOdyQIWUjE9R5R5iX/KMiNxJxjIwIjVVsiXjmwr6eE+W/z3n6mg/6O4JASWMbBcRWkx4CQfqIvTEw== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 1/20/26 19:06, Suren Baghdasaryan wrote: > On Fri, Jan 16, 2026 at 2:40 PM Vlastimil Babka wrote: >> >> We now rely on sheaves as the percpu caching layer and can refill them >> directly from partial or newly allocated slabs. Start removing the cpu >> (partial) slabs code, first from allocation paths. >> >> This means that any allocation not satisfied from percpu sheaves will >> end up in ___slab_alloc(), where we remove the usage of cpu (partial) >> slabs, so it will only perform get_partial() or new_slab(). In the >> latter case we reuse alloc_from_new_slab() (when we don't use >> the debug/tiny alloc_single_from_new_slab() variant). >> >> In get_partial_node() we used to return a slab for freezing as the cpu >> slab and to refill the partial slab. Now we only want to return a single >> object and leave the slab on the list (unless it became full). We can't >> simply reuse alloc_single_from_partial() as that assumes freeing uses >> free_to_partial_list(). Instead we need to use __slab_update_freelist() >> to work properly against a racing __slab_free(). >> >> The rest of the changes is removing functions that no longer have any >> callers. >> >> Signed-off-by: Vlastimil Babka > > A couple of nits, but otherwise seems fine to me. > > Reviewed-by: Suren Baghdasaryan Thanks! > -static struct slab *get_partial_node(struct kmem_cache *s, >> - struct kmem_cache_node *n, >> - struct partial_context *pc) >> +static void *get_partial_node(struct kmem_cache *s, >> + struct kmem_cache_node *n, >> + struct partial_context *pc) > > Naming for get_partial()/get_partial_node()/get_any_partial() made > sense when they returned a slab. Now that they return object(s) the > naming is a bit confusing. I think renaming to > get_from_partial()/get_from_partial_node()/get_from_any_partial() > would be more appropriate. OK, will do. >> - } >> + freelist = get_partial(s, node, &pc); > > I think all this cleanup results in this `freelist` variable being > used to always store a single object. Maybe rename it into `object`? Ack.